In aerobic organisms, reactive oxygen species (ROS), such as hydroxide (OH), singlet oxygen (1O2), hydrogen peroxide (H2O2), and superoxide (O2–) ions are produced during aerobic respiration, which causes serious oxidative damage to biomolecules in the body. Hence, the removal of ROS, particularly O2–, is of primary importance as it reacts with H+ to produce other toxic ROS species like H2O2 and OH.
This is achieved by metalloenzymes called superoxide dismutases (SODs). These enzymes possess metal ions (like Ni, Fe, Mn, Cu, and Zn) in their active centers that catalyze the decomposition of O2– to H2O2 and O2. In this regard, low molecular weight Cu(II) complexes have gained importance as functional SOD models that exhibit high SOD activity. However, they are limited by their tendency to become toxic to the biomolecules after the release of Cu(II).
